Trait Observer

Source

pub trait Observer:
    Send
    + Sync
    + 'static {
    // Required method
    fn observe(&self, event: &Event);

    // Provided method
    fn observes_shadow_outcomes(&self) -> bool { ... }
}

Expand description

Receives every public diagnostic. Failures (returned errors or panics) never change a cache, source or maintenance result.

Required Methods§

Source

fn observe(&self, event: &Event)

Receive one event. Called inline on the cache’s own path under panic isolation, so it should return quickly and never block.

Provided Methods§

Source

fn observes_shadow_outcomes(&self) -> bool

Whether this observer consumes shadow validation outcomes.

Shadow validation is diagnostic work that exists only to be observed, so the cache admits a shadow job only when the observer opts in by returning true. The bundled metric exporters opt in.